Rozhen Observation Calendar

Which nights are best for a target over the coming weeks. The astronomy mark (darkness × altitude × Moon) is computed for every night; the weather and the overall mark exist only where Open-Meteo has a forecast (the next four days) or ERA5 history (past nights) — the rest is honestly blank.

2046-03-31astronomy score per night — click a bar for that night2046-04-29

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2046-03-31 Sat	—	unknown	—	79.2° 14:20	8.13	25%	82.8°
2046-04-01 Sun	—	unknown	—	79.2° 14:20	8.07	18%	71.3°
2046-04-02 Mon	—	unknown	—	79.2° 14:15	8.02	11%	59.9°
2046-04-03 Tue	—	unknown	—	79.2° 14:10	7.96	6%	48.7°
2046-04-04 Wed	—	unknown	—	79.2° 14:05	7.91	2%	37.7°
2046-04-05 Thu	—	unknown	—	79.2° 14:00	7.85	0%	27.1°
2046-04-06 Fri	—	unknown	—	79.2° 14:00	7.8	0%	18.2°
2046-04-07 Sat	—	unknown	—	79.2° 13:55	7.74	2%	14.4°
2046-04-08 Sun	—	unknown	—	79.2° 13:50	7.68	6%	19.4°
2046-04-09 Mon	—	unknown	—	79.2° 13:45	7.63	11%	29.2°
2046-04-10 Tue	—	unknown	—	79.2° 13:40	7.57	18%	40.6°
2046-04-11 Wed	—	unknown	—	79.2° 13:40	7.51	27%	52.8°
2046-04-12 Thu	—	unknown	—	79.2° 13:35	7.46	37%	65.4°
2046-04-13 Fri	—	unknown	—	79.2° 13:30	7.4	48%	78.4°
2046-04-14 Sat	—	unknown	—	79.2° 13:25	7.34	59%	91.8°
2046-04-15 Sun	—	unknown	—	79.2° 13:25	7.28	70%	105.5°
2046-04-16 Mon	—	unknown	—	79.2° 13:20	7.23	80%	119.4°
2046-04-17 Tue	—	unknown	—	79.2° 13:15	7.17	88%	133.4°
2046-04-18 Wed	—	unknown	—	79.2° 13:10	7.11	95%	147.1°
2046-04-19 Thu	—	unknown	—	79.2° 13:05	7.05	99%	159.4°
2046-04-20 Fri	—	unknown	—	79.2° 13:05	6.99	100%	165.6°
2046-04-21 Sat	—	unknown	—	79.2° 13:00	6.94	98%	159.7°
2046-04-22 Sun	—	unknown	—	79.2° 12:55	6.88	94%	148.1°
2046-04-23 Mon	—	unknown	—	79.2° 12:50	6.82	87%	135.5°
2046-04-24 Tue	—	unknown	—	79.2° 12:45	6.76	79%	122.8°
2046-04-25 Wed	—	unknown	—	79.2° 12:45	6.7	70%	110.3°
2046-04-26 Thu	—	unknown	—	79.2° 12:40	6.64	60%	98.2°
2046-04-27 Fri	—	unknown	—	79.2° 12:35	6.59	50%	86.3°
2046-04-28 Sat	—	unknown	—	79.2° 12:30	6.53	41%	74.6°
2046-04-29 Sun	—	unknown	—	79.2° 12:25	6.47	32%	63.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2046-03-31&days=30"
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&days=30&format=csv" -o m31-calendar.csv

One row per night: score_astronomy always, score_weather / score only where a forecast or history exists (null otherwise, with weather_source saying which), best window, dark hours, Moon illumination and separation, transit. 7–60 nights. Errors: 400 with invalid_date or target_unresolved. Results are cached for six hours; calculation version 2026-10-10.1.